Third rail cover board

ABSTRACT

The electrically insulative cover board has an upstanding sidewall and a laterally projecting top portion extending longitudinally of an electrified third rail for protecting the third rail from inadvertent electrical contact therewith. The inside sidewall of the cover is open to allow a traveling electrical contactor to make electrical contact with the third rail. The cover is attached to the third rail by means of electrically insulative clamping brackets. The upstanding sidewall of the rail cover board includes at least one longitudinally directed laterally protruding convolution for strengthening the cover board against lateral bowing and to act like a cantilever spring to allow a controlled amount of downward vertical deflection of the top cover under a vertically applied load.

United'States Patent [191 Landis Apr. 23, 1974 THIRD RAIL COVER BOARD Primary Examiner-M. Henson Wood, Jr. [75] Inventor: Robert L. Landis, Los Altos, Calif. Assistant Exammer D' Keen [73] Assigneez ill]; 23312; Sales Company, Los 57] ABSTRACT The electrically insulative cover board has an upstand- [22] Paul 1 ing sidewall and a laterally projecting top portion ex- [21] Appl. No.: 297,290 tending longitudinally of an electrified third rail for protecting the third rail from inadvertent electrical contact therewith. The inside sidewall of the cover is ggb ijgi open to allow a traveling electrical contactor to make [58] Fieid 29 R 30 electrical contact with the third rail. The cover is at- 1 tached to the third rail by means of electrically insulative clamping brackets. The upstanding sidewall of the [56] References Cited rail cover board includes at least one longitudinally directed laterally protruding convolution for strength- UNITED STATES PATENTS ening the cover boardagainst lateral bowing and to 725,622 Z1933 Hornung 191/30 act like a cantilever spring to allow a controlled R27,07l 19 l Somes 191/23 A amount of downward vertical deflection of the top cover under a vertically applied load.

10 Claims, 2 Drawing Figures 1 THIRD RAIL COVER BOARD DESCRIPTION OF THE PRIOR ART have access to the electrified third rail via the open side of the rail cover. The closed sidewall portion of the cover was vertically planar extending into an arched top portion projecting over the rail. This coverboard was secured to and supported from the third rail by means of a plurality of generally inverted J-shaped brackets spaced at approximately -foot intervals along the direction of the third rail.

The problem with this prior art type of third rail cover and support structure was that brackets would either fail under a certain vertical load, such as that produced by dropping a 250-pound weight from 18 inches onto. the top cover portion, .or the sidewall would bow outward allowing excessive downward deflection of the top cover inbetween adjacent brackets.

SUMMARY OF THE PRESENT INVENTION The principal object of the present invention is the provision of an improved third rail cover board and support for same. V

In one feature of the present invention, the cover board includes an upstanding sidewall portion and a laterally directed top wall portion, said sidewall portion being provided with a longitudinally directed, laterally protruding convolution for strengthening the sidewall against undesired lateral deflection under vertical loads on the cover board.

In another feature of the present invention, the sidewall of the cover board is fixedly secured to the electrified third rail at points of attachment below the longitudinally directed laterally protruding convolution in the sidewall of the cover board such that the top portion of the cover board, under vertical load, is allowed to pivot a laterally directed top cover portion projecting over V the third rail while allowing an electrical contactor to downwardly about a longitudinal axis slightly above the points of attachment, whereby the convoluted sidewall portion and the top cover portion function as a spring biased cantilever unit.

In another feature of the present invention, the cover board is secured to the third rail by means of clamping brackets having a lateral vertical web portion and an inner flanged lip portion facing the third rail which is contoured to conform to the bottom and lower flanged portion of the third rail for securely gripping the third rail.

In another feature of the present invention, the clamping bracket includes a detachably secured clip portion for gripping the lower flanged portion of the electrified rail.

In another feature of the present invention, an O-ring seal is provided between the clip portion of the clamping bracket and the remaining body portion of the bracket to seal off a possible electrical leakage path between the electrified third rail and the means for securing the clip to the main body portion of the clamping bracket. 1

Other features and advantages of the present invention will become-apparent upon a perusal of the following specification taken in connection with the accompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective viewof a portion of a rapid transit track system employing an electrified third rail and the prior art cover board, and

FIG. 2 is an enlarged sectional view of that portion of the structure of FIG. 1 delineated by line 22 and showing the cover board of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. I, there is shown a section of the concrete support structure 10 which may be of the type utilized in tunnels or aerial structures to support a rapid transit trackway. In accordance with usual construction techniques, the structure 10, which may be either a preformed member or a member formed in place, is installed in place and left. unloaded for a predetermined period of time in order to account for normal structural settling. Subsequently, slabs 12 are poured to design grade and the rails 14 are affixed directly thereto by means of fasteners 16. An electrified third rail 18 is insulatively supported from the concrete structure 10 via the intermediary of insulative supports 20 placed at intervals along the trackway. An electrically insulative prior-art open-sided cover board structure 22 is fixedly secured to the electrified third rail 18 via inverted J-shaped brackets 24 disposed at convenient intervals along the third rail as of every 10 feet.

The prior art cover board 22 included a generally planar vertically upstanding closed sidewall portion 26 terminating in a laterally directed arched top portion 28. The problem with this prior art cover board structure 22 is that when the top portion 28 of the cover board is subjected to relatively high impact top vertical loads,.such asthat produced by dropping a 250-pound weight from 18 inches onto the cover board, the brackets 24 often fail or excesshfe deflectioiTd tion of the cover board isexperienced due to outward lateral bowing of the vertical sidewall portion 26 of the cover board 22.

Referring now to FIG. 2, there is shown an electrically insulative cover board structure 32 incorporating features of the present invention. The cover board structure 32 includes a longitudinally directed generally vertically upstanding closed sidewall portion 34 and a generally inwardly laterally directed downwardly arched top. portion38 terminating at a free edge por- Y and lower longitudinally directed, inward laterally protruding convolutions 42 and 44,. respectively, for strengthening the sidewall portion 34 against lateral inflame;-

bowing of the sidewall under vertical loads applied to the top portion 38 of the cover board 32. In a typical example, the upper convolution 42 protrudes laterally inwardly by approximately 1.125 inches and has an inside radius of curvature R, of approximately fiveeighths of an inch. The lower convolution 44 projects laterally inward by approximately seven-eighths of an inch and has an inside radius of curvature R of onehalf inch.

Clamping brackets 46 are disposed at approximately -foot intervals along the third rail 18 for fixedly securing the cover board structure 32 to the rail 18. The clamping brackets 46 are made of an electrically insulative material, such as glass reinforced resin (fiberglass), and each includes a vertical laterally directed web portion 48 as of inch fiberglass and a contoured flanged lip portion 50 having an axial extent in the direction of the longitudinal axis of the rail 18 of approximately 4 inches.

1 The outside vertical lip portion 52 of the clamping bracket 46 is contoured to mate with the lower convoluted portion of the sidewall 34 of the cover board 32, whereas the inner top' lip portion 54 of the flange 50 is contoured to conform to the bottom and outside lip portion of bottom flange of the electrified rail 18.

A pair of laterally directed studs 56 and 58 are molded into the web portion 48 of the clamping bracket 46. The cover board 22 is fixedly secured to the clamping bracket 46 via a nut 58 and cadmium plated steel washer 60. An upstanding detachable clip 62, as of it; inch thick glass reinforced resin (fiberglass) is fixedly secured to-the clamping bracket 46 via stud 58 and nut 64 which clamps down on the clip 62 via the intermediary of a cadmium plated steel washer 66. A square boss portion 68 surrounds the laterally directed stud 58 and mates with a square aperture 70 in the clip 62 to assure that the clip 62 does not rotate relative to the clamp 46.

An O-ring seal 72 is disposed about the periphery of the square aperture 70 in the clip 62 to provide a liquid tight seal between the inner end of the main body portion of the clamp 46 and the clip 62, such that an electrically conductive liquid path is prevented between the electrified rail 18 and the nut 64 via the spaces between the clip 62 and the clamp 46. In this manner, an operator tightening the nut 64 for tightening the clip 62 would not be subjected to an inadvertent electrical shock through such a liquid conductive connection. The clip 62 includes an outwardly directed lip 74 conforming to and engaging the lower flanged portion of the electrified rail 18 for clipping the rail 18 to the clamping bracket 46. In a typical example, the clip 62 has an extent along'the direction of the rail 18 of approximately 4 inches.

In operation, the upper and lower convolutions 42 and 44 in the sidewall portion of the cover board structure 32 serve to provide stiffening for the sidewall 34 while the upper convolution 42 permits the upper cantilevered top portion to pivotably deflect downwardly around a longitudinal axis slightly above the points of attachment of the sidewall 34 to the bracket 46 such that the entire top cantilevered portion 38 can deflect downwardly under the vertical loads rather than concentrating the vertical load in one or more brackets, as was experienced in the prior art structure. Replacement of the cover board structure 32 is facilitated by removing nuts 58 and washers and pulling the cover board outwardly over the studs 56.

Another advantage of the cover board 32 is that as the cantilevered top portion 38 pivots about pivoting axis, the inner lip portion 40 deflects downwardly and inwardly of the rail 18 to lend even further insulative protection against contact with the electrified rail 18.

What is claimed is:

1. In a cover board for covering an electrified third rail:

an electrically insulated cover board structure for covering an electrified third rail to prevent inadvertent electrical contact with the electrified rail, said cover board structure being elongated in the direction of the longitudinal axis of the rail and having an open side portion permitting electrical contact with the rail by a traveling electrical contactor which passes through the open side portion of said cover board structure into engagement with the electrified rail;

said cover board structure including, and upstanding sidewall portion to be disposed along the outside lateral edge of the electrified rail for covering the outside of the third rail, a top cover portion for extending laterally across the top of the electrified rail from the upper terminus of said sidewall portion, said sidewall portion including means defining points of attachment for attaching said sidewall portion to a support means for supporting said cover board relative to the third rail, said sidewall portion including a longitudinally directed lateral convolution for strengthening the sidewall portion of said cover board against lateral bowing deflection, said convolution being disposed above said points of attachment of said sidewall portion to the support structure so that a substantial length of said top and sidewall portions of said cover board structure pivotably deflect as a cantilever section about a longitudinal axis of said cover board under a downwardly directed load on said top cover portion of said cover board structure.

2. The apparatus of claim 1 including, support means for rigidly attaching said sidewall portionof said cover board structure at said points of attachment to the third rail.

3. The apparatus of claim v1 wherein said sidewall portion includes a second longitudinally directed laterally projecting convolution disposed below said points of attachment of said sidewall portion to the third rail to provide a further restraint against lateral bowing of said sidewall portion.

4. The apparatus of claim 2 wherein said support means includes a laterally directed clamp means for clamping to the third rail, said clamp means being made of an electrically insulative material.

5. The apparatus of claim 4 wherein said clamp means includes, a laterally directed main body portion, and an upstanding electrically insulative clip portion detachably securable to said main body portion for gripping the lower flange portion of the electrified rail.

6. The. apparatus of claim 4 wherein said clamp means includes, a laterally directed vertical web portion having an inner flanged lip portion facing the third rail which is contoured to conform to the bottom and outside lower flanged portion of the third rail for securely gripping the third rail.

7. The apparatus of claim 5 including, a threaded fastener means for detachably securing said clip portion to said main body portion of said clamp means, a liquid tight O-ring seal disposed around said threaded fastener means between said clip portion and said main body portion of said clip to prevent an inadvertent electrical contact path via a liquid path between said electrified third rail and said threaded fastener means.

8. In a cover board for covering an electrified third rail:

an electrically insulated cover board structure for covering an electrified third rail to prevent inadvertent electrical contact with the electrified rail, said cover board structure being elongated in the direction of the longitudinal axis of the rail and having an open side portion permitting electricalcontact with the rail by a traveling electrical contactor which passes through the open side portion of said cover board structure into engagement with the electrified rail; said cover board structure including, an op standing sidewall portion to be disposed along the outside lateral edge of the electrified rail for covering the outside of the third rail, a top cover portion for extending laterally across the top of the electrified rail from the upper terminus of said sidewall portion; 7 support means for rigidly attaching said sidewall portion of said cover board structure to said third rail, said support means including a laterally directed clamp means for clamping to the third rail, said clamp means being made of an electrically insulative material;

said clamp means including a laterally directed main body portion and an upstanding electrically insulative clip portion detachably securable to said main body portion for gripping a lower flanged portion of the electrified rail.

9. The apparatus of claim 8 wherein said clamp means includes, a laterally directed vertical web portion having an inner flanged lip portion facing the third rail, said flanged lip portion being contoured to conform to the bottom and outside lower flanged portion of the third rail for securely gripping the third rail.

10. The apparatus of claim 8 including, a threaded fastener means for detachably securing said clip portion of said clamp means to said main body portion of said clamp means, a liquid tight O-ring seal disposed around said threaded fastener means between said clip portion and said main body portion of said clip to pre- 'vent an inadvertent electrical contact path via a liquid path between said electrified third rail and said threaded fastener means. 

1. In a cover board for covering an electrified third rail: an electrically insulated cover board structure for covering an electrified third rail to prevent inadvertent electrical contact with the electrified rail, said cover board structure being elongated in the direction of the longitudinal axis of the rail and having an open side portion permitting electrical contact with the rail by a traveling electrical contactor which passes through the open side portion of said cover board structure into engagement with the electrified rail; said cover board structure including, and upstanDing sidewall portion to be disposed along the outside lateral edge of the electrified rail for covering the outside of the third rail, a top cover portion for extending laterally across the top of the electrified rail from the upper terminus of said sidewall portion, said sidewall portion including means defining points of attachment for attaching said sidewall portion to a support means for supporting said cover board relative to the third rail, said sidewall portion including a longitudinally directed lateral convolution for strengthening the sidewall portion of said cover board against lateral bowing deflection, said convolution being disposed above said points of attachment of said sidewall portion to the support structure so that a substantial length of said top and sidewall portions of said cover board structure pivotably deflect as a cantilever section about a longitudinal axis of said cover board under a downwardly directed load on said top cover portion of said cover board structure.
 2. The apparatus of claim 1 including, support means for rigidly attaching said sidewall portion of said cover board structure at said points of attachment to the third rail.
 3. The apparatus of claim 1 wherein said sidewall portion includes a second longitudinally directed laterally projecting convolution disposed below said points of attachment of said sidewall portion to the third rail to provide a further restraint against lateral bowing of said sidewall portion.
 4. The apparatus of claim 2 wherein said support means includes a laterally directed clamp means for clamping to the third rail, said clamp means being made of an electrically insulative material.
 5. The apparatus of claim 4 wherein said clamp means includes, a laterally directed main body portion, and an upstanding electrically insulative clip portion detachably securable to said main body portion for gripping the lower flange portion of the electrified rail.
 6. The apparatus of claim 4 wherein said clamp means includes, a laterally directed vertical web portion having an inner flanged lip portion facing the third rail which is contoured to conform to the bottom and outside lower flanged portion of the third rail for securely gripping the third rail.
 7. The apparatus of claim 5 including, a threaded fastener means for detachably securing said clip portion to said main body portion of said clamp means, a liquid tight O-ring seal disposed around said threaded fastener means between said clip portion and said main body portion of said clip to prevent an inadvertent electrical contact path via a liquid path between said electrified third rail and said threaded fastener means.
 8. In a cover board for covering an electrified third rail: an electrically insulated cover board structure for covering an electrified third rail to prevent inadvertent electrical contact with the electrified rail, said cover board structure being elongated in the direction of the longitudinal axis of the rail and having an open side portion permitting electrical contact with the rail by a traveling electrical contactor which passes through the open side portion of said cover board structure into engagement with the electrified rail; said cover board structure including, an opstanding sidewall portion to be disposed along the outside lateral edge of the electrified rail for covering the outside of the third rail, a top cover portion for extending laterally across the top of the electrified rail from the upper terminus of said sidewall portion; support means for rigidly attaching said sidewall portion of said cover board structure to said third rail, said support means including a laterally directed clamp means for clamping to the third rail, said clamp means being made of an electrically insulative material; said clamp means including a laterally directed main body portion and an upstanding electrically insulative clip portion detachably securable to said main body portion for gripping a lower flanged porTion of the electrified rail.
 9. The apparatus of claim 8 wherein said clamp means includes, a laterally directed vertical web portion having an inner flanged lip portion facing the third rail, said flanged lip portion being contoured to conform to the bottom and outside lower flanged portion of the third rail for securely gripping the third rail.
 10. The apparatus of claim 8 including, a threaded fastener means for detachably securing said clip portion of said clamp means to said main body portion of said clamp means, a liquid tight O-ring seal disposed around said threaded fastener means between said clip portion and said main body portion of said clip to prevent an inadvertent electrical contact path via a liquid path between said electrified third rail and said threaded fastener means. 